Question

fan and medal for best answer :)

an expression is shown below:
f(x)=-16x^2+8x+3
part a.) what are the x intercepts of the graph of f(x)? show work

part b.) is the vertex of the graph of f(x) going to be maximum or minimum? what are the coordinates of the vertex? justify answer and show work

part c.) what are the steps you would use to graph f(x)? make sure you can use answer obtained in part a and part b to draw graph.

Answer 1

just sub 0 for f(x) and solve for x. I would use the quadratic formula for part a

Answer 2

part b is a maximum and we know that because of the -16x^2 that means it is concave down

Answer 3

use x=-b/2a to find the vertex location

Answer 4

then take that value and sub it into the original to find the y value of the vertex

Answer 5

i don't know how to use the quadratic formula

Answer 6

I would graph using the vertex, y intercept and x intercepts

Answer 7

http://www.purplemath.com/modules/quadform.htm

Answer 8

if you are in Algebra I, do not bypass the quadratic formula. You will need it throughout your entire math studies.

Answer 9

thanks

Answer 10

how do you get the vertex coordinates @precal i don't get it

Answer 11

do you have a graphing calculator so that you can verify the graph and the solutions

Answer 12

coordinate of the vertex is ( 1/4, 4)

Answer 13

how would you answer part c?

Answer 14

let me check it with my graphing calculator

Answer 15

not exactly

Answer 16

a=-16 b=8 and c = 3

Answer 17

what?????

Answer 18

x=-b/2a
x=-(8)/(2*-16)
x=-8/-32
x=8/32
x=1/4
sorry you were correct, my calculator gave me x=.2500078

Answer 19

I just showed you how to find the x coordinate of your vertex, now sub x=1/4 into the function and solve for your y value

Answer 20

confused :/

Answer 21

Are you in Algebra 1?

Answer 22

yes

Answer 23

why don't you graph it and see what it looks like? You should focus on the critical parts of the quadratic.
where it crosses the x axis, those locations are called the x intercepts
where it crosses the y axis, that location is called the y intercept
and the vertex because that is where the graph has symmetry ie x=1/4 is your axis of symmetry